(a) Field of the Invention
The present invention relates to a control method of an electric vehicle. More particularly, the present invention relates to a control method of an electric vehicle that can reduce fuel consumption and cost by efficiently controlling a motor provided in the electric vehicle.
(b) Description of the Related Art
To solve environmental pollution problems and to develop alternative energy, an electric vehicle has been developed.
The electric vehicle includes a motor for driving the vehicle and a high voltage battery for supplying power to the motor. The battery is an energy source used to drive the motor, and can supply power to the motor through an inverter.
A MTPA (maximum torque per ampere) control method is one of motor control methods. The MTPA control method sets a current map by sweeping current supplied to the motor. The MTPA control method controls the motor by mathematical modeling, but there is a problem that nonlinearity of the motor cannot be represented by a mathematical equation when the motor is controlled by the equation.
In order to make up for the problem, a motor control method that sets a current map from an operating point that minimizes output current of the motor is used. At this time, the operating point can be calculated from an equal torque region obtained by current sweep. However, since the motor control method should consider a loss of the motor and the inverter, there is a problem that measuring factors (for example, motor torque, motor current, motor voltage, power factor of the motor, DC voltage, and DC current) are increased. As such, when various measuring factors are used, an output result is distorted by an error of a measuring sensor. Further, since various measuring factors are used, a measuring system is complicated and the system manufacturing cost is increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.